CFD study on the flow distribution of an annular multi‐hole nozzle

Annular multi-hole nozzles are commonly used to disperse one or more types of material in chemical processing, agricultural irrigation, firefighting, and so on. In this study, the LES (large eddy simulation) method combined with the VOF (volume of fluid) model was employed to investigate the impacts of inlet volume flow rate, hole diameter, and distance downstream of nozzle on the flow distribution of the nozzle. To quantify the uniformity of the flow distribution, the non-uniformity parameter, wetted area, and uniformity index were introduced. The sprays ejected from the nozzle are separated into two modes in accordance with their structure, namely partially impinging sprays (PIS) and fully impinging sprays (FIS). Compared with the three other types of nozzles investigated in this study, the nozzles with a 400 mu m hole diameter can achieve the most uniform flow distribution of the nozzle outlet. In addition, the nozzle with larger holes and a higher inlet volume flow rate can easily achieve a large wetted area. However, the nozzle with smaller holes and a relatively low inlet volume flow rate is more inclined to achieve a uniform flow distribution. The larger the inlet volume flow rate, the larger the holes that should be adopted to achieve a relatively uniform flow distribution.